Greetings, all. Theater is finally just about done as you can see in these pics. I'm going to be making DIY acoustic panels, probably 2" Roxul 60 (2x4 ft sheets). My question is where to put them. I am thinking one behind each speaker (total of 6). One at the first and second reflection points for the L and R speakers (total of 4), and one on the back door for a total of around 11. Can anyone offer any other input please? Dimensions of the room are 21x15x8. Thanks a lot, looking forward to hearing your opinions.

Greetings, all. Theater is finally just about done as you can see in these pics. I'm going to be making DIY acoustic panels, probably 2" Roxul 60 (2x4 ft sheets). My question is where to put them. I am thinking one behind each speaker (total of 6). One at the first and second reflection points for the L and R speakers (total of 4), and one on the back door for a total of around 11. Can anyone offer any other input please? Dimensions of the room are 21x15x8. Thanks a lot, looking forward to hearing your opinions.

I did mine at first reflection points on the left and right wall and one behind the seating. I did not use them behind the screen.

The primary reflection points we should be concerned with are from the front mains. I also treat the secondary reflection points, which in this case should be right around where the side surrounds are located.

Some people like myself are only doing the second reflection point for the L/R speakers. You may want to try that first to see if you like it. It allows for a little more of an open soundstage. I had some panels on my first reflection points as well and ended up taking them down. It really is a personal preference. You may also really not need anything to the side of the seating area or to the rear side of you. Maybe just treat the rear wall enough so you don't get too much echo back there.

Some people like myself are only doing the second reflection point for the L/R speakers. You may want to try that first to see if you like it. It allows for a little more of an open soundstage. I had some panels on my first reflection points as well and ended up taking them down. It really is a personal preference. You may also really not need anything to the side of the seating area or to the rear side of you. Maybe just treat the rear wall enough so you don't get too much echo back there.

In my last theater I did first and second but you bring up a good point, too. I'm trying to think ahead because Roxul 60 is very expensive to have shipped and I continue to be amazed that I can't find any around here. The more I buy the less expensive each piece becomes but if I don't need them then I'd just be wasting money. I am however also going to do a few bass traps and I believe I can use that material for those as well. Any opinion on that aspect of things?

In my last theater I did first and second but you bring up a good point, too. I'm trying to think ahead because Roxul 60 is very expensive to have shipped and I continue to be amazed that I can't find any around here. The more I buy the less expensive each piece becomes but if I don't need them then I'd just be wasting money. I am however also going to do a few bass traps and I believe I can use that material for those as well. Any opinion on that aspect of things?

If you make them thick like Mocs123 said you can go ahead and make panels for the first and second reflection points and if you do like it better without the first reflection point you can use those panels elsewhere like the back of the room.
That's what I did. My panels are 4" thick and ended up using the first reflection panels as rear corner bass traps.

If you make them thick like Mocs123 said you can go ahead and make panels for the first and second reflection points and if you do like it better without the first reflection point you can use those panels elsewhere like the back of the room.
That's what I did. My panels are 4" thick and ended up using the first reflection panels as rear corner bass traps.

With that 4" thickness did you put a space between the back of the panel and the wall? I'm also curious to know how you hung them? Certainly a lot of options.
EDIT: One more question if I may. With superchunk bass traps would it do me any good to put some on top of the Devastators I'm building? The Devs will go right in a corner and are 4' tall. That leaves me with about 4' above them to put a bass trap. Seems to me that would be a good use of space?

With that 4" thickness did you put a space between the back of the panel and the wall? I'm also curious to know how you hung them? Certainly a lot of options.
EDIT: One more question if I may. With superchunk bass traps would it do me any good to put some on top of the Devastators I'm building? The Devs will go right in a corner and are 4' tall. That leaves me with about 4' above them to put a bass trap. Seems to me that would be a good use of space?

When the panels were against the wall I just put them flat against the wall with no spacer.
The super chunk certainly won't hurt there. To see if truly need them you would have to do measurements first, but if you have extra material putting it there would be nice.

Outstanding, thank you for your input! I'm trying to order as much as I think I'll need all at once to try to save on shipping, which is ridiculously priced. I still can't fathom why I can't find any locally but that's a whole other story.